/Engine/Source/Editor/AddContentDialog/Public/FeaturePackContentSource.h
Returns a list of additional files (including the path) as specified in the config file if one exists in the pack file.
true if config file was read and parsed successfully
bool GetAdditionalFilesForPack ( [TArray](API\Runtime\Core\Containers\TArray)< [FString](API\Runtime\Core\Containers\FString) > & FileList, bool & bContainsSource )